If an Engineer like to design Slab by sheet Excell according program results of M1-1 and M2-2 only with ignoring M1-2 should set M1-2 Modifier equal zero, is this a proper solution?
ACI -447-18: Design Guide for Twisting Moments in Slabs give the answer for this question , yes set M1-2 equal zero is a proper sollution but you should know considering M1-2 equal zero larger deflection than those predicted by analyses with nonzero stiffness of twisting moment, the defliction ratio should not to exceed 25 percent.